1. Field of the Invention
The present invention relates to a process for producing chloroprene. More particularly, it relates to a process for producing chloroprene by a dehydrochlorination of 3,4-dichlorobutene-1, by contacting it with a metal alkoxide of tetrahydrofurfuryl alcohol.
2. Description of the Prior Arts
It has been known to use an aqueous solution of an alkali metal hydroxide in a dehydrochlorination of 3,4-dichlorobutene-1. In accordance with the conventional process, the reaction temperature is too high whereby the production of the by-product of 1-chlorobutadiene-1,3 is increased and chloroprene is easily polymerized. The by-production of 1-chlorobutadiene-1,3 causes a decrease of the yield of chloroprene and also a deterioration of physical property of the chloroprene polymer obtained therefrom if 1-chlorobutadiene-1,3 separated before the polymerization.
It has been proposed, as an improved process, to add an alcohol to the aqueous solution of an alkali metal hydroxide to increase the reaction velocity and to decrease the by-production of 1-chlorobutadiene-1,3 as disclosed in Japanese Unexamined Patent Publication No. 116,306/1978 and No. 106,907/1975 and Japanese Examined Patent Publication No. 11,406/1972.
It has been also proposed to provide various processes for dehydrochlorination of 3,4-dichlorobutene-1 with a metal alkoxide in a non-aqueous system as disclosed in Japanese Examined Patent Publication No. 44921/1976, Japanese Unexamined Patent Publication No. 86403/1976 and U.S. Pat. No. 3,936,508, No. 3,896,181 and No. 4,104,316.
The alcohols used in these processes include methanol, ethanol, isopropanol, n-butanol, sec-butanol, tert-butanol and 2-butoxyethanol. These are chain compounds which are azeotropically distilled with water and accordingly, the alcohol should be separated from the aqueous phase.